a. Field of the Invention
This invention relates to seals, and more particularly to a seal assembly disposed between relatively rotatable parts such as a stationary housing with a rotating shaft passing through the housing.
b. Background Art
In applications involving relatively rotating members such as a rotating shaft extending through a stationary housing, it may difficult to form an effective seal between the members, especially when one member moves relative to the other member in a direction parallel to an axis about which the members rotate. For example, in an application in which a rotating shaft passes through a stationary housing, it may necessary to seal oil within the housing and to prevent dirt or other contaminants from entering the housing. In such an application, a seal assembly may be used in which a seal is formed between an elastomeric element of the seal assembly and the rotating shaft. If, however, the rotating shaft moves axially relative to the elastomeric element as the shaft rotates about its axial axis, the seal between the elastomeric element and rotating shaft may fail. In particular, as the shaft moves axially outwardly relative to the elastomeric element, the shaft may collect dust and other abrasive particles. Then, as the shaft moves axially towards the elastomeric element, the dust and other abrasive particles may become trapped between the rotating shaft and elastomeric element and may also become embedded within the elastomeric element. As the shaft continues to rotate, the trapped and embedded abrasive material may score the shaft and the elastomeric element to such an extent that oil may eventually leak through the seal formed between the shaft and the elastomeric element.
Accordingly, what is needed in the art is an improved seal assembly for sealing relatively rotating members.